Vocabulary Challenge
Baitball – a dense mass of fish underwater which is usually a protective response to the presence of a predator
Blowhole – the opening on top of the head from which a dolphin or whale breathes
By-catch – animals that are caught accidentally or intentionally and disposed of back into the sea as they are not the target species sought by the fishermen; often dead or injured, these animals do not have the market value making it worth catching these animals for profit.
Coastal Ecotype – the shallow water sub-species of Atlantic bottlenose dolphins that is adapted for warm, shallow waters with a smaller body and larger flippers for greater maneuverability and heat dissipation; they generally can be found in bays, inlets, marshes, rivers and waters along the open ocean that are often at depths of 10 feet or less.
Countershading – a form of camouflage that allows an animal to blend in with the background making it difficult to be spotted by a predator; in the case of bottlenose dolphins, one side of the body matches the background seen from above and one side of the body matches the color of the background seen from below.
Dorsal Fin – the fin on a whale’s back that is made of collagen and is often used to help identify individual animals Echolocation – the ability to create sounds and listen to the returning echoes of those sounds when they bounce off objects underwater, allowing the animal to discriminate size, shape, speed, density and direction of an object in question.
Entanglement – when an animal has a body part that becomes wrapped with a piece of debris that cannot be removed, often causing injury, illness or even death
Flukes – the rear fins on a whale’s tail that act as flattened paddles for power; they are made of fibrous connective tissue called collagen and are completely without bone, cartilage or muscle.
Growth Layer Groups – the layers of dental growth that are seasonally added to a toothed whale’s tooth which allow scientists to accurately determine the age of the animal
Home Range – an area in which individuals or groups regularly move about during day-to-day activities
Logging – a behavior of floating at the surface which is often seen when a dolphin is sleeping or resting
Mammal – an animal that shares the following traits: born live, has hair, breathes air, warm-blooded and nurses their young
Mammary Slits – the openings near the genital area of a whale that protect and conceal the nipples from which a calf would nurse
Marine Debris – trash that has made its way to the sea
Melon – the forehead of the dolphin which is filled with a fatty fluid that acts as an acoustic lens to focus the sounds used for echolocation
Myoglobin – is an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and found in abundance in the muscles of many marine mammals
Odontocetes – the family of Toothed Whales in which all members are born with teeth
Pectoral Fin – the front fins of a whale which have a bone structure similar to a human hand and arm and mostly function for stopping and steering
Peduncle – the muscular portion of a dolphin’s tail which provides power for swimming and runs from behind the dorsal fin to the base of the flukes
Rostrum – the extended upper and lower jaw of a dolphin; the lower jaw is filled with a fatty fluid and functions as an antenna for returning echoes received specifically for echolocation
Signature Whistle – a particular type of sound dolphins learn after born and are unique to each individual so that it can be used to identify them.
What type of habitats do bottlenose dolphins like?
Atlantic bottlenose dolphins are found in saltwater rivers, bays, estuaries, marshes and in the open ocean. There are two ecotypes: the smaller inshore dolphins and the larger offshore dolphins. The inshore, coastal ecotype is often found in water 10 feet or less and do not need to dive very deep to catch food. The local area in which individual or groups of dolphins move about during day-to-day activities is called a home range.
What does a dolphin eat?
Dolphins are toothed whales – Odontocetes – and are opportunistic feeders, eating most any species of fish available. Some types of fish consumed are herring, capelin, mackerel, squid, mullet and sardines. Some dolphins also eat crustaceans, cephalopods, even small rays or sharks. Their interlocking teeth are used to grab prey, not for chewing. Fish that are too big to swallow can be shaken or be rubbed against the bottom to break into pieces. Funny Fact: most of our dolphins eat their fish head-first but the sea lions at Dolphin Encounters eat their fish tail-first!
How do dolphins catch their food?
Dolphins use a variety of strategies to catch their food and tend to vary based on region, season, age, sex and reproductive classes. Hunting methods are learned by calves primarily through observing their mothers and have been seen to proliferate throughout a population. Dolphins can chase fish into a shallow environment or, in some cases, on to mud flats. They can also slap a fish with their flukes, stunning the fish long enough to catch. Individual animals can use echolocation to locate fish that are hiding in the sandy bottom and dig them out. In deeper waters, dolphins may work as a team to herd fish into a dense mass called a baitball and take turns swimming through the ball to grab fish.
How does blubber help a dolphin?
Blubber — a layer of fat reinforced by collagen and elastic fibers — plays a number of important functions. It contributes to a dolphin’s streamlined shape which helps increase swimming efficiency. It is a storage of fat, which provides energy when food is in short supply. It helps reduce heat loss, which is important for thermoregulation when living in the ocean. It also is a measure of protection from predation, as predators must bite through this layer to reach vital organs. Blubber also serves as a temporary storage area for organic pollutants like PCBs and pesticides. At the top of the food chain, dolphins and whales are exposed to more pollutants as they accumulate from the large prey they consume. Eventually these toxins can be deadly if the blubber is metabolized when food is sparse or if a mother uses the blubber to generate milk for a nursing calf.
Are dolphins camouflaged?
Yes, countershading is a type of camouflage found in many marine species which makes it more challenging for a predator to detect them. By having a dark back, the animal will be difficult to see from above against the dark ocean depths. In contrast, the light belly of a bottlenose dolphin matches the sunlit surface waters when viewed by a shark from below.
If dolphins are mammals, where is their hair?
All mammals have hair at some point in their lives. A dolphin calf is born with just a few curly hairs on top of its rostrum which fall out soon after birth. The other traits of being a mammal are: born live, breath air, nurse their young and are warm-blooded. Up close you can even see where the hair follicles used to be!
Why is a dolphin’s skin so smooth?
Dolphins shed their outer layer of skin every two hours which creates a smooth body surface. To help slough the dead skin, the animals at Dolphin Encounters often rub on the sandy bottom, rubropes or other dolphins. Up close though, you can feel tiny ridges that scientists believe play a role in sensory function as well as help reduce drag. When touching the animals, you may even see the dead skin cells on your palm!
How fast can dolphins swim?
Bottlenose dolphins routinely swim about 3-7 mph. The maximum recorded swim speed of a dolphin swimming up before a vertical leap was 25 mph!
How do dolphins sleep?
Because they are air-breathing mammals living in the water, dolphins cannot sleep the way that you and I can. Dolphins must remain conscious at all times. To do this, dolphins rest by allowing half of their brain to go into a sleep state while the other half maintains awareness of the environment and breathing needs, which includes keeping one eye open. The side of the brain that is “sleeping” switches many times during the sleeping period. Cetaceans have the ability to swim while sleeping, but a common resting behavior seen is logging, in which the whale lays still at the surface of the water.
How long can an Atlantic bottlenose dolphin hold its breath?
On average, an Atlantic bottlenose dolphin can hold its breath for 5 – 7 minutes. Some of the reasons dolphins are so good at diving and holding their breathe include: the ability to exchange 80% of the lung volume on exhale, the ability to slow their heartbeat while diving, and the high abundance of myoglobin in their muscle which allows them to carry more oxygen in their muscle compared to humans.
What types of sounds do dolphins make?
Bottlenose dolphins are known to make three types of sounds: whistles, echolocation clicks and burst-pulse sounds. Dolphins develop an individually specific signature whistle within the first few months of life and this whistle remains the same throughout most if not all of their lives. They use these unique whistles to communicate their identity, location and, potentially, emotional state. Male calves have a signature whistle similar to their mother’s whistle while female calves do not.
What is echolocation?
Echolocation is a dolphin’s ability to receive information by sending sound waves into their environment and then analyzing the returning echoes after they have bounced off of objects in the water. The clicks made for echolocation are focused into a concentrated beam as they pass through the melon. The returning echoes are received via the lower jaw which is hollow and passes the sound waves through a fatty fluid. Echoes from those sounds can determine the size, shape, structure, composition, speed and direction of an object underwater. Dolphins can detect objects from over 70 meters away!
How can you tell how old a dolphin is?
Dolphins only have one set of teeth their entire life. As a dolphin ages, it produces growth layer groups of dental material. If a tooth is removed, age can be estimated by examining a sliced section of a tooth and counting these layers – much like counting the rings on a tree.
What is an Atlantic bottlenose dolphin’s lifespan?
In marine mammal facilities accredited by the Alliance of Marine Mammal Parks and Aquariums, such as Dolphin Encounters, the average lifespan is over 25 years. In the wild, the average lifespan is roughly HALF of that. Some reasons are that animals under our care are protected from predators and pollution as well as provided a healthy balanced diet every day. In addition, facilities provide important preventative health care through voluntary medical behaviors and procedures, including dental, pre-natal, ultrasound exams to name a few.
Do dolphins have any predators?
Yes! Sharks and killer whales are natural predators of dolphins. But not all sharks are deadly – and some species of shark, like the cookie cutter shark, would prefer that their dolphin victims stay alive after an attack. The cookie cutter shark is a relatively small shark, and it makes its living by biting off small chunks of its victim’s flesh – usually in a circular pattern. By taking a small painful plug of flesh from a dolphin, the shark will get its meal, and the dolphin will live to see another day. Dolphins are also known to sometimes be quite bothersome to some species of shark, such as nurse sharks, who typically dine on other kinds of wildlife such as bottom invertebrates and some fish.
Are Atlantic bottlenose dolphins threatened or endangered?
The species as a whole is not endangered, threatened or vulnerable although localized populations may be. The International Union for the Conservation of Nature (IUCN) lists the bottlenose dolphin as a species of least concern, however threats to the animals – and their habitat – are increasing. Compared to offshore dolphins, coastal dolphins may be at greater risk to human-related threats due to their greater proximity to human activities such as boating, water pollution and habitat loss.
What are the most common threats to dolphins in the wild?
Serious injuries and death from recreational and commercial fishing are the most serious threats dolphins face. When an animal gets some form of debris caught on its body, this entanglement is difficult and sometimes impossible to remove, causing infection, loss of limb, drag that slows the animals down and makes it more prone to predator. When caught as by- catch, dolphins are often injured or killed by the time they are returned to the water as unwanted catch.
How can I help dolphins?
Being respectful of dolphins is the best way to help them. Keeping the Ocean clean of marine debris – trash that has made its ways to the sea — and pollutants by REDUCING your trash, REUSING items and RECYCLING makes the sea a safer place for all marine life. Learn more about protecting marine mammals in the wild at the Watchable Wildlife Guidelines!